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Airdog df100 pressure adjustment


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My fuel pressure kept going up and down.  The adjustment "jam" nut (9/16) I can turn but the nut behind it (3/4") also moves.  Can't get wrench on it because of bracket is blocking wrenching room.  I ground down an old wrench, still not enough room for both wrenches. Problem is created because I turned the airdog 180 so I could use old fass bracket without drilling new/more holes. 

 

Question...if I hang pump on fence and suck fuel out of bucket to set pressure will pressure be the same when hooked up to vp44?  

Thought I would bend over vinyl hose to create back pressure.  

 

I don't want to keep taking pump off and on...thought hanging on fence to adjust would be easier. And only have to set one time. Dreaming or good idea?

Thanks

 

(Edit... pump on fence tottaly independent of vp44)

 

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Ok thanks

...I  was thinking a pump really wouldn't matter what is was pumping and pressure would be the same.   Except I have no idea what vp44 does when idling but suspect some fuel goes through to lube it...which would relieve some pressure.  How much pressure relieved...i don't know.  

Guess I'll get my share of diesel baths taking off to adjust pressure, bolt back up, take pressure reading...then repeat till pressure is right.

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19 minutes ago, AH64ID said:

What do you mean by pressure going up and down? How much of a swing?

 

 

The AD regulates flow to acheive steady pressure. It should be constant until you reach the flow capabilities of the pump. 

 

Pressure would go up and down 5-7 psi.  Not all at once but over time, one week to the next.  The bolt that I can't get to keeps whatever is inside tight.  And the "Jam" nut keeps it tight.  Doesn't do much good to tighten up jam bolt if the bolt it's keeping tight is loose.  (Pic found on line) the nut at top right is what I'm trying to tighten..  The big nut keeps in (whatever parts) and "Jam" nut keeps that bolt tight. Pretty hard to get wrenches in there.  Can't use socket because when you can't tighten the other nut is covered by the socket which prevents wrench access. Can't find an Airdog part diagram, if I knew what was behind the big bolt I might take it out and put on a spacer, so wrenches could adjust. But don't want to remove big nut and have bunch of springs and bearings fall out.  

1d 005-air-dog-fuel-system-duramax-diesel-chevy-silverado.jpg

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Having never adjusted an AD this comes with a grain of salt. But I’ve worked with multiple regulators that appear the same. 

 

The large nut against the main housing should be right and doesn’t appear to be used for pressure adjustments. 

 

The next but outward is the jam nut for the pressure adjustment screw that is adjusted with a screwdriver. 

 

So once that large nut is tight you shouldn’t have to touch it. The 2nd nut should have zero effect on the tightness of the large nut. 

 

I’d tighten the large nut with a socket. Then adjust your pressure with a single wrench and a screwdriver. 

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I know how to adjust but can't wrenches in there to adjust with pump mounted.  That's why I'm wondering if I can adjust not mounted on truck and not connected to vp44.  

 

Think I'll noodle something out where pump is not mounted...but standing on top of something yet close enough to be hooked up to vp44 so i don't have to mount, adjust, take off then adjust again...and have to repeat till pressure is 19

 

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About every 6,000 to 10,000 miles a readjustment to fuel pressure is required to keep at the long lasting VP pressure of around 19 psi.

 

I advise to make a bracket allowing for a better mounting and access to the regulator whenever needed. Nothing like a truck set up right. You need a min. of 14 psi to keep the VP happy. Esp. on hot days accelerating uphill. It is so very important, (the min. 14 psi) otherwise you giving VP an accelerated wear.

 

Usually not doing the short cut is harder of course, but in the long run much reward is to be had.

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Thanks folks

Right now thinking 2 things.

 

1. Call airdog to see if it's right to put in longer bolt, or spacer so bolt head has more distance from bracket and i can use wrenches.

 

2. Grind out a really thin blade wrench made of 12 or 14 gauge metal.

 

(Edit about hour after previous post.  Learn something new every day.  I never knew "thin bladed" wrenches were available, other than speciality sizes one would buy for a particular job.  Amazon has them.  Going to get a set, should solve my access problem.)

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3 minutes ago, jlbayes said:

I had to take mine apart a couple times to adjust it. The larger nut is the jam and the slot is the pressure adjustment. It would fill up with dirt and lock up. Use a stubby wrench. It will fit.

 

 

Yes, but I think the OP is also referring to the larger nut still, which should hold the pressure regulation valve in and not be used for pressure adjustments. 

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11 minutes ago, AH64ID said:

Im still not tracking why you need a wrench on the inner/larger nut?

The larger nut that holds the regulator assembly to the pump housing can come loose when loosining the jam nut. You may have to hold the larger nut with a back up to prevent this. If it left loose you will have problems.

 

@015point9  I suggest you do as @JAG1 described re mounting your pump so it’s easily accesable.

 

when I had my raptor pump I had to adjust it sometimes and it was usually a two minute process. even doing it along side the road

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29 minutes ago, AH64ID said:

Yes, but I think the OP is also referring to the larger nut still, which should hold the pressure regulation valve in and not be used for pressure adjustments. 

 

He still needs to break it loose to move the actual pressure adjuster. Why the wrench is needed. A stubby fits in there. The airdog bracket is the same way as his fass is. In the freaking way.

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33 minutes ago, jlbayes said:

 

He still needs to break it loose to move the actual pressure adjuster. Why the wrench is needed. A stubby fits in there. The airdog bracket is the same way as his fass is. In the freaking way.

 

Looking at 01Cummins4Ever's response I think you're still talking about the adjustment nut and not the actual regulator nut (which isn't a nut but the regulator itself). 

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OP here...i don't have enough room for regular size wrenches.  Ordering a set of thin blade today.   After getting thin blades, if I still don't have enough room I 'm going to have to get another mounting bracket that has more room at top and side.

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9 minutes ago, Mopar1973Man said:

I'm so happy I've got the old "Check Ball and Spring" set up. Way too many issues with the adjustable regulator setups.

 

Agree...wish I would of known that before I bought.  

Also after taking a good look at the bracket the pump mounts to, it does not look like something any place (fass or airdog) would sell.  When the Fass was put in around 2005 I  think the mechanic welded up couple pieces of metal and called it a bracket.  But still better job than my welding.

I'll be so glad to get pump set up right. And move on.   At present time pressure gauge is mechinal screwed in directly to airdog with one of Vulcan's wrapped around running board.  "A" pillar is dangling loose on dash board waiting for fuel pressure gauge.  But have to relocate trans gauge somewhere.  After installing fuel tank, fuel gauge no longer works.  Problems...problems.  getting problems worked out one by one.  Good I don't need truck as daily driver.  For the last year,  truck has gone no more than 6 miles from house.  

I appreciate all the help on here.  Everybody has been very helpful. Thank you.

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